Pressure-retaining-valve device.



T. A. HEDBNDAHL. PRESSURE RETAINING VALVE DEVICE.

APPLICATION FILED JANJG, 1911.

1, 1 O8, 1 70. Paten fid Aug. 25, 1914.

| i u r I? k l A /7 m MW M WITNESSES INVENTOR 7H5 NORRIS PETERS 00., PHOTD-LITHQ, WASHINGTON. D. c.

UNITED STATES PATENT OFFICE.

THEODORE A. HEDENDAl-IL, OF DENVER, CQLQRADO, ASSIGNUR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF PITT OF PENNSYLVANIA.

QEURGH, PENNSYLVANIA, A CORPORATION PRESSURE-RETAINING-VALVE DEVICE.

Patented Aug. 25, 1914. Serial No. 602,820.

To all whom it may concern Be it known that I, THEoDoRnA. HEDEN- DAHL, a citizen of the United States, residing at Denver, in the county of Denver and State of Colorado, have invented new and useful Improvements in Pressure-Retaining- Valve Devices, of which the following is a specification.

This invention relates to fluid pressure brakes, and more particularly'to an automatic pressure retaining valve device.

In the operation of railway trains, especially on grades, it is often desirable to hold the brakes applied by retaining a certain degree of pressure in the brake cylinder, so that the train pipe pressure may be increased to thereby eflect the recharging of the auxiliary reservoirs without releasing the brakes.

Various retaining valve devices have heretofore been devised for this purpose, the form commonly employed comprising a valve subject to the load of a weight or a spring for controlling the exhaust of air from the brake cylinder through the triple valve exhaust port, and a cock having a position for permitting the usual free exhaust from the brake cylinder and another position for cutting the pressure retaining valve device into action.

It will be evident that the braking force and consequently the brake cylinder pressure necessary to hold the train under con trol will vary according to the amount of grade and while'a retaining valve device of the above character may be adjusted to retain the desired brake cylinder pressure for one grade such degree of pressure may not be suflicient for another grade.

The principal object of my invention is to provide a pressure retaining valve device adapted to be automatically adjusted at will by the engineer so as to hold any desired degree of pressure in the brake cylinder.

In the accompanying drawing, Figure 1 is an elevational view of a triple valve device, with my improvement applied thereto; Fig. 2 a central sectional view of a modified form of pressure retaining valve device embodying my invention; Fig. 3 a similar view of another modification; and Fig. 4; a similar view of still another modification.

According to the construction illustrated in Fig. 1 of the drawings, the pressure retaining valve device comprises a casing 1 having a chamber 2 communicating with the triple valve exhaust port of a triple valve device 3 through a pipe 4, and a chamber 5 communicating with the train pipe 6 through a pipe 7.

A diaphragm 8 separates the two chambers 2 and 5 and is adapted to operate a valve 9 for controlling communication from chamber 5 to an atmospheric port 10. The cham ber 2 is also provided with an outlet pipe 11 having a cook 12 adapted in one position to open communication from the chamber 2 to the atmosphere and in another position to close said communication. A spring 1?) acts on the side of the diaphragm subject to the pressure of chamber 2.

The spring 13 may be adjusted for any desired pressure, but preferably is such as to exert a pressure of 60 pounds per square inch on the diaphragm 8.

With the spring 13 adjusted at 60 pounds, if it is desired to retain fluid under pressure in the brake cylinder upon releasing the brakes, the cook 12 is turned to its closed position on each car and assuming that the train pipe pressure is increased to the usual standard pressure of 70 pounds, the triple valve parts are shifted to release position and fluid from the brake cylinder flows through pipe 4 to chamber 2 and acts on the diaphragm 8 in the same direction as the spring 13. If the pressure in the brake cylinder plus the pressure of the spring 13 exceeds the train pipe pressure of 70 pounds opposing said pressures then the valve 9 will be opened thereby and fluid will be vented from the brake cylinder until the pressure therein falls to a point at which the combined pressure of the spring and the brake cylinder is less than the pressure in the train pipe, then the valve 9 is closed and the remaining fluid is retained in the brake cylinder. If the spring 13 is set at 60 pounds then the pressure retained in the brake cylinder will be 10 pounds at 70 pounds train pipe pressure. If it is desired to retain a greater degree of pressure in the brake cyl inder the train pipe pressure is increased a corresponding amount above the normal train pipe pressure, for example, if the train pipe pressure is increased to 80 pounds in releasing the brakes, then 20 pounds will be retained in the b 'ake cylinder, and it the train pipe pressure is increased to 90 pounds, 30 pounds will be retained and so on.

The port 14; which affords communication from pipe 7 to chamber 5 is preferably made small, so that if any leakage should occur past the diaphragm 8, the same would not be sufiicient to eiiect the train pipe pressure to any substantial degree.

If it is desired to permit the usual tree exhaust from the triple valve, the cook 12 on each car is of course turned to its open position.

In Fig. 2 is shown a modified construction in which the spring 13 is dispensed with and instead a ditl'erential diaphragm is employed. In this instance a casing 15 is provided having a diaphragm chamber containing a dilierential diaphragm comprising a diaphragm 16 subject on one side to the brake cylinder pressure in chamber 2 and a smaller diaphragm 17 subject on one side to the train pipe pressure, the two diaphragms being operatively connected together and the space between them being open to the atmosphere through a port 18. The brake cylinder pressure retained with this construction will be directly proportional to the train pipe pressure, and if the area of the diaphragms are in the ratio of 1 to l, for example, then the brake cylinder pressure retained will be one-fourth of the train pipe pressure.

The construction illustrated in Fig. 3 is similar to that shown in Fig. 2 except that a differential piston is employed instead of a differential diaphragm. In this form, casing 19 is provided with a piston chamber containing a piston 20 and a piston chamber containing a small piston 21, the two pistons having respective engaging stems 22 and 23 to permit cooperation of the pistons to control the operation of the vent valve 9. Any leakage past the pistons 20 and 21 is disposed of by providing relief ports 2 The relative areas of the pistons 20 and 21 may be the same as that of the dia phragm shown in Fig. 2 and the operation of this form will evidently be the same as that of the construction shown in Fig. 2. Preferably the piston 21 is provided with a seating rib 25 adapted to engage a seat 26 in its lower position so as to prevent leakage from the train pipe around the piston.

In Fig. 4: a construction is shown in which the retaining valve device is embodied in the triple valve cap, so as to avoid breaking pipe joints in case it is found necessary to remove the retaining valve for adjustment, cleaning or repairs. In this construction, the triple valve cap 27 is constructed with an integral portion 28 containing chambers 5 and 2 separated by piston 29 which operates the valve 9. The chamber 5 is connected by passage 30 in the casing of the triple valve cap 27 with the train pipe side of the triple valve piston 31 and chamber 2 is connected by passage 32 in the cap with passage 33 in the triple valve body 84 leading to triple valve exhaust port 35. It will be evident that the operation of this form will be the same as that described in connection with the other constructions hereinbefore described, and if desired, a cock may be provided similar to the cock 12 for controlling a free exhaust from the chamber 2 and the brake cylinder.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a fluid pressure brake, the combination with a train pipe and a valve device operated by a reduction in train pipe pressure for effecting an application of the brakes, of a pressure retaining valve device comprising a valve for controlling the release of air from the brake cylinder and a movable abutment subject in one direction to brake cylinder pressure tending to open the valve and in the opposite direction to train pipe pressure tending to close the valve.

2. In a fluid pressure brake, the combination with a train pipe and triple valve device, of a valve for controlling the release of air from the brake cylinder through the triple valve exhaust port, a movable abutment subject in one direction to train pipe pressure tending to close the valve and in the opposite direction to brake cylinder pres sure tending to open the valve, and means for neutralizing the efi'ect of the train pipe pressure on said abutment to a predeter mined extent.

3. In a fluid pressure brake, the combination with a train pipe and triple valve device, of a valve for controlling the release of air from the brake cylinder through the triple valve exhaust port, a movable abutment subject in one direction to train pipe pressure tending to close the valve and in the opposite direction to brake cylinder pressure and the pressure of a spring.

4L. In a fluid pressure brake, the combination with a train pipe and triple valve de vice, of a pressure retaining valve device subject to train pipe pressure "for controlling the exhaust of air from the brake cylinder and operated to retain a relative degree of pressure in the brake cylinder corresponding with the degree to which the train pipe pressure is increased.

5. In a fluid pressure brake, the combination with a train pipe and triple valve device operated by variations in train pipe pressure to apply the brakes, of a pressure retaining valve device subject to train pipe pressure for controlling the exhaust of air from the brake cylinder and operating to retain pressure in the brake cylinder according to the amount of increase in train pipe pressure.

6. The combination with a train pipe, variations in pressure in which operate to apply the brakes, of a pressure retaining valve device operated by a predetermined increase in train pipe pressure for retaining pressure in the brake cylinder varying according to the degree of increase in train pipe pressure. 7. The combination with a train pipe, variations in pressure in which operate to apply the brakes of a pressure retaining valve device subject to train pipe pressure and adapted to vary the degree of pressure retained in the brake cylinder according to the amount of increase in train pipe pressure.

8. The combination with a train pipe, variations in pressure in which operate to apply the brakes of a pressure retaining valve device subject to train pipe pressure and adapted to vary the degree of pressure retained in the brake cylinder according to the amount of increase in train pipe pressure above the normal degree of train pipe pressure.

In testimony whereof I have hereunto set my hand.

THEODORE A. HEDENDAHL.

Witnesses:

J. P. LIVINGSTON, HOYT Dow.

come! of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

